After Katrina: Roofs remain source of concern

View full size(Courtesy Pensacola Opera)Ivan's wrath is evident as waves thunder ashore in the Florida Panhandle in mid-September 2004. "The Hurricane Monologues" uses diaries, journals, essays and e-mail by those who lived through the disaster to depict the hours before, during and after the catastrophic hurricane that ravaged Pensacola.

The blue roof has become a post-hurricane cliché along the Gulf Coast. The damage under those plastic tarpaulins is the most common impact that a storm has on houses.

Materials, building methods and code enforcement have all improved since 2005’s Hurricane Katrina. But Press-Register interviews of code officials in more than 20 cities and counties in coastal Alabama and Mississippi found that ensuring well-built roofs is a major challenge in building inspection.

The interviews revealed a disparity in code enforcement.

A number of jurisdictions, for example, don’t routinely inspect roofs that are being replaced. Such a project in unincorporated Baldwin County doesn’t even require a permit. Without such checks, existing homes may not get as much benefit when building standards are improved in an area.

Roof damage can be widespread, even when winds aren’t very high. For example, a survey of 933 homes in Houma, La., found that 65 percent suffered roof damage in 2008’s Hurricane Gustav. That’s even though the top gust measured in the survey area was 78 mph.

The average damaged home lost 12 percent of its roof covering.

“It’s the first thing that starts to go,” said Tim Reinhold, chief engineer with the Institute for Business & Home Safety, a Tampa, Fla., group that pushes for stronger construction standards and is supported by insurers.

Mike Howell, the chief building official for Baldwin County, said blown-off shingles led to a lot of houses getting soaked inside by Hurricane Ivan.

“It would have $5,000 worth of shingles missing, and it would have $80,000 worth of water damage,” Howell said.

One measure of roof damage after Ivan? The Federal Emergency Management Agency distributed 46,000 tarps in Alabama, including 16,000 in Mobile County and 4,000 in Baldwin County, officials said at the time.

The American Society of Civil Engineers, which makes predictions about how high the strongest 3-second gust will be in a storm, says that areas close to the Gulf, from Ocean Springs to Orange Beach, should build to withstand 140-mph winds. Dauphin Island and Pascagoula must build to withstand 150-mph winds.

The strength of a roof starts with its attachment to the rest of the house. Connectors are supposed to anchor the frame to the rafters. If a house has a gable, it’s supposed to be braced so it won’t blow down.

It’s a big concern for the Mississippi Windstorm Underwriting Association, the state insurer of last resort, said association manager Joe Shumaker. The association gives 12 percent discounts to policyholders who can prove their roofs are properly connected and braced.

Next is the roof decking — plywood or oriented strand board that goes down on top of the rafters. When shingles blow off, the boards are all that’s left to keep out water and wind.

In the past, many builders used staples to attach decking to rafters. That’s still theoretically allowed under building rules in places like Daphne or Pascagoula, but only if an engineer says it will work.

Staples, though, have been found to come undone at lower wind speeds than nails.

“If you find staples, no matter what the spacing, your roof sheathing is not well-connected to the roof framing,” the state of Florida advises homeowners. A number of Alabama and Mississippi communities have banned staples.

The safety institute and others advocate using asphalt tape to cover seams in the decking and block water. But taping, which adds a few hundred dollars to costs, is rare in much of the region.

“I’ve never seen it done,” Satsuma building inspector Thomas Briand said. “I’ve never even heard of it.”

After the decking comes the liner — what roofers and inspectors call underlayment. Traditionally, felt has been the choice. But experts say felt is weaker than new synthetic underlayment, either nailed on or self-adhesive.

A number of Baldwin County jurisdictions have banned felt. But cost-conscious roofers and consumers may shy away from synthetic.

“If you roof according to manufacturers’ instructions, I think you’re going to get a decent roof out of it,” said Michele Coats, planning director for Jackson County.

View full size(Press-Register/Mike Kittrell)Johnny C. Carpenter, chief building inspector for Mobile County, begins an inspection of framing and roof sheathing at a house under construction in the Magnolia Springs subdivision Wednesday, August 25, 2010, in west Mobile, Ala.

Baldwin’s Howell said roofers were taught to nail at the top of an asphalt shingle, but manufacturers want shingles nailed farther down, so nails go through the top edge of the shingle underneath. Inspectors said that error happens less, now that manufacturers print a line to guide nailers.

Roofers are supposed to use six nails to a shingle, inspectors said, but they’re not sure that always happens. They say checking shingle installation is one of the hardest parts of their job, because an inspector usually doesn’t have time to stand around and watch roofers work all day.

“It’s difficult to catch the full process,” said Saraland building official Mike Black.

There’s also the problem of lifting up shingles to check nailing. That may break the adhesive seal that holds shingles together and void warranties, officials said.

Jurisdictions such as Mobile, Mobile County and Pascagoula only inspect replacement roof jobs on request. No permit is required for re-roofing in Baldwin County, Howell said, because staff can’t inspect effectively.

“I don’t have enough people to drive a 100-mile round trip to look at someone installing a roof system,” Howell said. “From a common-sense standpoint, we can’t stay there the whole time.”

Overall, code officials say they’re working to keep blue tarps away after the next storm, but there is still work to be done.

“Roofing’s an issue with everybody, and my house too,” said Saraland’s Black.